My CEL came back on (I have this real neat software for my laptop, a product called OBDCOM, comes with disk and cable for under $90), anyway it came up with code P0141 O2 Heater Circuit (Bank 1, Sensor 2). This is the behind cat sensor right? Any suggestions, is this a common problem?

 

Usualy when one hooks up a code reader, one gets a code. Usualy this is not the problom.

I do not know which one it is that is bad. But, I would venture the one behind the cat. Yes, this is a common problom. I am guessing its a 96 because its a OBDII code. The truck is 13 it is (The sensor) probobly just worn out.

 

Yes the code refers to the second sensor (the one behind the cat).

Does the software you are useing allow you so see data from the sensor? By that I mean the actual voltage reading that would be going back to the computer. It sounds like the heated portion of the sensor has gone bad.

If you can get readings from the o2 sensors, the 1st cat o2 sensor reading should change from .1 volts to .9volts on a constant basis. The second o2 sensor reading should stay basiclly constant ( this means the cat is doing it's job).

I would say that if it is the original sensor, then yes it is time to replace it.

 

yes, this software and cable (OBDCOM) is for 96 and newer, it is OBD II, it does do live monitoring very well displaying it in either gauges or in a display field or both. I'll say here now that if you have a laptop this is definitely better than having a scan meter that only displays codes, live monitoring is awesome, everything from volts, vacuum, timing advance, O2 voltages and much more, the software and cable was under $100 shipped, and the company replies to all questions. Anyway back to my sensor, the heater element is over 4K ohms so that is definetly bad, I think it is supposed to be below 10 ohms. My understanding is this sensor is not responsible for trimming the fuel air/ratio but monitors for irregularities in the performance of the cat. I'm not sure if this trouble would prevent it from running in closed loop, I'm guessing it is running closed loop, I emailed OBDCOM and asked them what part of the monitoring display indicates open or closed loop What do you think of eBay for buying a sensor there, they have some universal sensors that requires splicing the connector on, I have read that it's better to stick with the Ford sensor, any thoughts?

 

Ranger, yes the software displays the acual voltage and waveform, the two sensors up front are nearly identical with the swing up and down like a sawtooth waveform, the cat sensor is pretty much flat line.

 

Do you know if it is running in open or closed loop?

Normally the motor runs in open loop until certain parameters are meet. It might be that the engine has to be warmed up to a certain temp, or whatever. If it doesn't meet this specific parameter then it stays in open loop and doesn't use any inputs from sensors. I'm not sure if the behind the cat o2 sensor can cause this or not. Alot of things have changed over time and I don;t remember.

You need to check and see if it is in open or closed.

If the behind cat o2 sensors does the saw tooth patern then that means the cat is not working properly any more. It sounds like the heater inside the o2 sensor has wore out.

There is a motorcraft website that you can lookup the codes per year vehicle and it explains the codes. I'll see if I can find it, it is pretty helpful.

 

that is my question as well, is it in closed loop after warm up or is that cat sensor enough to keep it open. I emailed OBDCOM and asked them if there was an indication if it was in open or closed loop, here is his reply.........Yes, one of the live monitors (on the live data/gauges) screen shows open/closed loop status.
Mike
I'm going to check it out

 

I use Autotap and mine has that option to see if it is in open or closed loop. It's been a while since I used mine and can't remember what it is under.

How many miles are on your truck? If you wanted to save some money you might try getting on at a salvage yard and see if it fixes the problem.
There has been times that I went to pull a part and found brand new items that I needed on old trucks there.

 

this is my first Ford truck, it has no rust and just getting ready to turn 70,000 miles, a five speed. I think I'm gonna go with a sensor off eBay, right now the only thing that bothers me is the CEL, the truck runs fine, later today I'm gonna hook up the diagnostics and confirm it goes into closed loop after warm up

 

That would be the best thing to do. Make sure it is going into closed loop.

If you clear the codes does it come back while driving or after the second start cycle? By that I mean once you clear it and then drive it the light doesn't come back on until you turn it off and then start it again.

If I remember right the po141 code is only checked once per drive cycle.